Accurate location of mobile terminals, e.g. mobile telephones, in a wireless system, for example, a cellular telephone communication system, has been a difficult challenge. Several techniques have been proposed and partially developed to address this problem, but there remains a need for a technique with greater precision of location. It is generally desirable that such a location system be relatively low cost, require little or no modification to existing user hardware and software, and not disrupt operation of the communication system.
Prediction of received signal strength of signals from mobile terminals that may be operating in actual environments may be a difficult task. A source of difficulty may be a lack of available information about a propagation environment, at least in a precision that may be required for an accurate application of a theory of wave propagation, e.g. electromagnetic wave theories presented by James Clerk Maxwell. This lack of information may be inherent in a modeling problem as a propagation environment may be changing dynamically, and also may be random in nature. An assumption may be made of a certain physical model and may not be directly related to an actual physical environment. It is generally desirable that such a model be based more on signal strength measurements from an actual environment.
Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals indicate corresponding, analogous or similar elements. It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.